Electric heater



y 5, 1930. c. c. ABBOTT 1,770,823

ELECTRIC HEATER Filed on. 15. 1925 Inventor: CHarIeS OAbbott.

HLS Attorney.

Patented July 15, 1930 UNITED STATESPATENT OFFICE CHARLES C. ABBOTT, OI PITTSFIELD, MASSACHUSETTS, ASSIGNOB TO GENERAL ELEG- TBIC comm, A. CORPORATION OF NEW YORK EI'JEG'JSBJIG HEATER Application fled October 15, 1925. Serial No. 02,021+.

My invention relates to electric heaters, and more particularly to moisture proof electric heaters, and has for its object the provision of improved means for sealing heaters of this type.

My invention has special application to electric heaters of the encased or sheathed type in which the heater is enclosed in an outer metallic protective casing and is thereby made impervious to moisture except at..

the points where the terminals the casing.

In carrying out my invention, I shape the encased heating unit so that its ends are adj acent each other and provide a receptacle on the protective casing of the unit adjacent its ends in which is an insulating sealing material which embeds the ends of the casing and the terminals projecting therefrom, as de-, scribed and claimed in my co-pending appli project from cation Serial No. 595,191, filed October 17,

1922. In accordance with my present invention I close the receptacle by means of a solid insulating block which is provided with apertures for the terminals and with an extension extending into the insulating material whereby the block is secured.

For a more complete understanding of my invention reference should be had to the accompanying drawing in which Fig. 1 is a fragmentary plan view partly in section of an electricheater embodying my invention; Fig. 2 is a fragmentary side elevation view also partly in section of the heater shown in Fig. 1 "while Fig. 3 is a fragmentary sectional view taken along the line 3- -3 of Fig. 1 looking in the direction of the arrows.

Referring to the drawing, I have shown my invention in one form in combination with a trically insulating seahng material 25 provided in the receptacle, this sealing material helical coil sheathed heating unit of the t described and claimed in 1 my Patent 0.

1,367,341, dated February 1,1921. Briefly,

sulating material 13. The insulating material 18 may be compacted to a hard dense mass having good heat conductivity in any suitable manner, for example, by reducing the diameter of the sheath after the unit has been assembled. Such units can be bent easily into any desired shape, and as shown, the heating unit 10 is bent in the form of a hairpin. The resistance conductor 12 has its ends secured to terminals 14 and 15, which project -from the ends of the sheath and are electrically insulated from the sheath. I

As shown, the central portion of the heating unit is cast in a mass or body of metal 16, such as cast iron, whereby the unit may be secured to the body or member to be heated, as, for example, by means of suitable clamp ing bolts passing through notches 17 and 18 provided in the ends of the body 16. As

shown, the body 16 has a flat surface 19 which may be secured in good heat conducting relation to. a similar flat surface on the part to be heated. In the casting of the heating unit in the body 16 a plurality of metallic washers 20 are secured at intervals along its length whereby the heating unit is upheld in the properposition in the mould, while the metal is cast around it. These washers remain in the casting.

Substantial lengths of the ends of they heating unit reject from the cast body 16 and these en 21 and 22 are bent upward with respect to the surface 19 so as to be out of the way. These ends of the heatin unit are brought near each other and in or er to provide a moisture proof seal a receptacle member 23 is secured to them. This receptacle member .has apertures in its bottom through which the ends of the heating unit -are'inserted so as to project somewhat into the interior 'of the receptacle after which the receptacle is secured to the sheath by brazed or welded joints 24 and 24. An elecbeing poured into the receptacle while heated to a liquid condition. The sealing material embeds the outer ends of the eating units and the terminals, thoroughly sealing the ends of the heating unit. y suitable sealing material may be used, such as bakelite or an asphaltic compound.

The receptacle is further closed by means of a solid cylindrical block of suitable insulating material 26 provided with apertures 27 and 28 for the terminals. This block which may be made of lava, is slightly larger than the mouth of the receptacle and rests on the upper edge of the receptacle, completely closing it. It is provided with an extension 29 on its lower side which projects downward into the sealing material 25. Preferably the block 26 is put in place while the scaling material is still soft 50 that the sealing material is free to flow around the extension 29 and secure the block in place upon hardening.

The block is further secured by means of contact clips 30 and 31, which are electrically connected to the ends of the terminals and seated firmly on the block. A cap 32 is provided, which is secured to the receptacle by means of screws 33 and encloses the contact clips 30 and 31. An insulating bushing 34 is provided in the cap through which conductors may be led to the contact clips in order to connect the heater to a suitable source of electrical supply.

What I claim as new and desire to secure by Letters Patent of the United States is 1. A water-tight seal for heating units provided with a metallic sheath which has its ends substantially adjacent each other and from which electrical terminals project comprising a receptacle secured to said sheath near its ends so that said ends project into said receptacle, an insulating sealing material in said receptacle embedding the ends of said sheath and said terminals, a block of solid insulating material closing said receptacle and provided with apertures for said terminals, said block having an extension extending into said receptacle and embedded in said insulating material and a contact clip provided for each terminal and mounted upon the end thereof in engagement with said insulator so as to secure said insulator.

2. A water-tight seal for heating units provided with a metallic sheath which has its ends substantially adjacent each other and from which the terminals of an insulated resistance conductor project comprising a receptacle secured to said sheath near its ends so thatsaid ends project into said receptacle, an insulating sealing material in said receptacle embedding said terminals and the proleeting ends of said sheath, an insulator embedded in said sealing material closing said receptacle and provided with apertures for said terminals and a terminal clip provided for each terminal and mounted upon the end thereofin engagement with said insulator so as to secure said insulator.

In witness whereof, I have hereunto se my hand this 10th day of October, 1925.

' CHARLES C. ABBOTT. 

